Making artificial leather



35 ed product also is like leather permeab gases, unless the original impregnation by e. rest rem. n. A1830 OF I D, ASSIGNOR T RES? no, 0?

ING TIEICIAL THEE 58 for its basis sheet materials of the character described in the patent to Roland B. Respess No. 1,524,573 dated January 27, 1925. It is characteristic of that sheet material that at e preparatory stage of its manufacture it con- 0 sists of a sheet or unwoven fibres, impregnoted with a viscid, cementitious substance, but of loose or open texture, which, upon re ceiving a compressive treatment becomes compact-by the integration of previously .6 separateor imperfectly integrated fibre-coatings of the cementitious material. The completed product described in the said patent possesses the structural and physical propties of leather in substantial degree, and is,

indeed, stronger than many varieties or grades of leather of equal body thickness. Not only is the stage-product above alluded to permeable by-gasesthoughr resistant to penetration by waterbut the final compaitcementitious material be so controlled as to carry into association with'the fibres a proportion of the cementitious material so voluminous in its final coagulated, solidified, or dense condition that no interstices remain to permit permeation by gases, This matcrial, when completed by the rocess described in the said patent, has a du l-appearing 'surface and therefore requires the applicatmn of surface coatings or dressings it it is to simulate finished leather to the eye as well as in its structural and physical properties Surface coatings or dressings have been a plied 0 to such com leted material h spreading or dressing mac ines in the well own manner, substantially as has been thepractice in the manufacture of coated cloths, etc. for a long time, and have served thei tended purpose 5 satisfactoril exce twhen s bjected to conditions whic call or great tenacity of union between the material and its coating or dressingif the latter is to remainintegreted with the former.

3 9 An object oi the invention herein described no nmwin Application nee April 1, rear, Eerie! no. lenses, and 11; Great sump. April 7, 1

is to produce a surface-coated or dressed material of the character indicated in which the coating-film is so securely attached. to the fibrous material as to be practically insepae rable therefrom.

In the practice of this invention, advantage is taken of the structural peculiarities of the stage-product which appears in the manufacture of sheet material in accordance with the process described in the said patent. Instead of coating or surface-dressing the completed material, as heretofore, a loosely constructed sheet of unwoven fibres-sucli as cotton batting or wedding-is first imgregnated with VlSCld cementitious material-such as rubber or a rubber composition in a solvent vehicle thereof-intrudin this into the sheet essentially in the manner described in the said patent; second, the impregnated sheet is allowed, after the first step, to recover part of its original spacial dimension of thickness by virtue of the resiliency of the fibres of which it is composed, so that the impregnated sheet becomes reticular and easily permeuble by a fluid (air, in the specific case) which so acts upon the content of viscid cementitious material as to render it much more viscous and adhesively tenacious than it was when intruded into the assembla e of fibres, all substantially as set forth in t e said patent.

At this stage, the impregnated sheet is relatively soft and loose in texture, though considerably reduced in thickness from its original condition; the constituent fibres are each coated with adhesive cement which is in a condition of augmented tenacity and. adhe siveness adapted to bring about and retain a much closer union of the constituent materials u on further compressive treatment.

ill

en t e material has reached this intermeaddition to or substitution for the cellulosic first coating of said application, a waxy pigment-bearing coating applied in such a way as to increase the adhesive permanence of the surface layer or dressing, and produce a product generically fit for all of the usesof the relatively thin or upper leathers, such ,as for the uppers of shoes, shoe-linings, and miscellaneous leather manufactures such as handbags, purses, book-covers, belts and gloves. This application also relates to a composition of matter suitable for application to the said base material and concatenation with it according to this description.

If the original cementitious impregnant of the fibrous sheet be a rubber composition with gasoline, naphtha, or the like as a solvent vehicle, and the first coating or dressing composition be nitrocellulose extended or dissolved in amyl or ethyl acetate, with or without benzol, or a cellulose acetate extended or dissolved in acetone, the solvent constituent of the dressing remains in wetting contact with, and if benzol or like solvent is used, softens the rubber composition adhering to the surface fibres, in either .case forming local association between the soluble constituent of the dressingand the rubber already present,

and thus enhancing the intimacy of adhesive association between fibre, rubber and the surface layer and intruded interpenetrating extensions of the dressing material, which now ensues when the sheet material thus supplied with a surface-penetrating base coating or dressing, is subjected to a further compression, as in a calendering or embossing machine. Before finally compressing or calendering the material to its intended stateof adhesive integration of fibre-cement inclusion and coating inclusion there may be applied successive coatings of a surface dressing over the base-coat, allowing each coating to set before applyin the next; or the application of further surface coatings upon the base coating may be deferred until after the material with the base coating attached has been consolidated by calendering. In either case, each of the successive coatings is preferably of such character as to unite by strong adhesion with the coatin to which it is applied. The coatings maydie embossed as well as calendered, to produce whatever superficial appearance is desired. Calendering in some cases may follow embossing for special effects of grain.

When the base coating is applied as above described to the material in its intermediate stage of production and while it is reticular in structure and superficially permeable by a varnish-like coating material, the base coat envelopes the surface fibres, or portions of them, as well as intrudes or penetrates into the grosser cavities of the relatively open unfinished base material, (like the relation of plaster to lathing) so that upon being dried or set to a tacky consistency, the said coating is anchored or tied to the fibres of the sheet material both by adhesion and by intruded keys of the coating. When, at a later stage of manufacture,the coated sheet is heavily compressed, this anchorage or tying of the coating to the fibres, and to the cementitious adhesive material originally applied to the fibres, is rendered so tenacious and secure that the aggregate final finished coating or dressing (composed of several applications of dressing material) is so interlocked with the fibrous body and its cement that any attempt to pull the dressing from the sheetwill result in rupture of the latter. This result is effectively produced whether the coating material is cellulosic or waxy, or comprised of layers of each. It will be understood that the first layer or coating having interpenetrated a reticular texture of, the fibrous base of which each fibre bears a strongly adhesive coat, the

subsequent compression interlocks the coatthat the surface meshes of the reticular base fabric everywhere intrude into the coating, so that on compression the adhesion secured is in-part mechanical interlocking and in part adhesive union between the material of base and coating respectively. This relationship applies as well when the open reticular base is subjected to several coatings before compression especially if the first coating does not fill the available interstices, so that when set this coating itself has interstices to be filled by second or later coated layers.

Coating solutions compounded as follows, for an example, yield satisfactory results in application to material having the characteristics above indicated:

For the base coating, nitrated cotton cut or dissolved in any of its well-known solvents, e.. g. ethyl acetate, to form a 16 oz. solution, so-called (i. e. sixteen ounces of the solute to a gallon of the solvent). To this a pigment ground in castor oil may be added to give a desired color. The addition of castor oil or other softeners may be resorted to in sulficient quantity to producethe desired degree of pliability. When the ingredients used have been thoroughly mixed, the solution is then thinned by the addition of nitro cellulose solvent until the desired viscosity is obtained. A viscosity of about 28000 centipoises, as given by a Stormer viscosimeter, model 7 650- A, and calculated by the equations of Higgins & Pitman (Journal of Industrial and Engineering Chemistry, vol. 12,1920-page 587) is suitable to the purpose.

When a waxy finish of the leather substitute is desirable, the coating applied initially or in succession to the cellulosic coating is recommended to be prepared by the inclusion of a varnish gum and a hard wax in solution with borax and/or soap. The hard wax may be a vegetable or a mineral wax. For example, prepare with stirring a first solution of borax, 17 pounds; orange shellac flakes, 60 pounds; water, 40 gallons; prepare with heat and stirring a second solution, suspensionor extension, of white neutral soap flakes, 6 pounds; carnauba wax, 19 pounds; water, gallons. Mix in the ratio of from five to eight parts of the first solution to three parts of the second solution. The product is a smooth viscid paste, hard. but flexible when the water of emulsion or solution has evapotion, and su cient quantities of rated away, and not water-soluble thereafter to any practical extent. This dressing paste contacts without resistance to adhesion with the viscid rrubber cement of the base fabric. Pigments ma be ground in the second soluerfumes, such as the oils of Sassafras, citrone la, birch, origanum oil may be mixed with either solution to impart a desirable odor. This dressing may be spread on and intruded into the open pores of the fabric, with or without a first coating of colloidal material as above described, dried, and thereafter subjected to the described compacting pressure.

The varnish gum for the first solution is preferably a shellac which has not been subzetonic solvent.

Before or after the application of a coating of this waxy dressing, and after or during the heavy compressive integratign of the fabric by pressure necessary to thecompletion of the fibre-and-cement base fabric, the material may be subjected to embossing in imitation of any of the natural or artificial leather grains, or with any arbitrary pattern. When the dressing is set and dry, the surface may be subjected to any desirable treatment. For example, a liquid or powdered pigmenting coat in a contrasting color may be applied, and with or without this, the surface may be finished or polished by brushing or bufiing, or both.

The coated sheet, made as above described, has been found entirely adequate in many respects to the manufacture of shoes, novelties, pocket-books, trunk linings, book covers jectedto solution in any alcoholic, etheric' or terial described is subjected when usedas parts or as a whole of the leather-like parts of such articles have no effect on the coating, which remains tenaciously attached to the tough fibrous sheet material.

I claim:

1. Composition of matter adapted for coating an artificial leather of the kind having a cement-integrated unwoven fibrous base by application in the open reticular state of said base comprising a varnish gum, in solution, and a hard wax and a neutral soap dispersed in an aqueous menstruum.

agents, and a suitable pigment dispersed therein.

5. Composition of matter adapted for coating artificial leathers comprising a varnish gum and a wax respectively held in aqueous solution and in suspension by saponifying agents, and an odorous vegetable oil.

I 6. Composition of matter comprising a mixture of suitable proportions of first an aqueous solution of shellac in water with the aid of borax, and second of carnauba-wax dispersed in water with the aid of soap, one of said aqueous solutions carrying a suitable pigment dispersed therein in finely-divided homo eneous distribution.

7. omposition of matter comprising a mixture of a quantity of an aqueous solution of shellac in water with the aid of borax and of a lesser quantity of carnauba wax dispersed in water with the aid of soap, one of said aqueous solutions carrying a suitable pigment dispersed therein in finely-divided homo eneous distribution. a

8. omposition of matter comprising a mixture of suitable proportions of first an aqueous solution of shellac in water with the aid of borax, and second of carnauba Wax dispersed in water with the aid of soap, one of said aqueous solutions carrying a suitable pigment dispersed in finely-divided homogeneous distribution therein, and one of said solutions having dispersed therein a suit-- able quantity of an odorous vegetable oil.

Signed by me at Providence, Rhode Island, this 30th day of March, 1927.

' ROYAL K. ABBOTT. 

